Knife bolster



FIG. 1 is a perspective view of the knife bolster showing my new design;

FIG. 2 is a Left side view of the knife bolster showing my new design, the Right side view being a mirror view of the Left side;

FIG. 3 is a Top side view thereof;

FIG. 4 is a Bottom view thereof;

FIG. 5 is a Front view thereof; and,

FIG. 6 is a Rear view thereof.

The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a knife bolster, as shown and described. 